Remove holders for runtime type information.

sdk/lib/_internal/compiler/implementation/ssa/builder.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of ssa;
 
 /**
  * A special element for the extra parameter taken by intercepted
  * methods. We need to override [Element.computeType] because our
  * optimizers may look at its declared type.
@@ skipping 2776 matching lines @@
       instruction = new HIs(type, <HInstruction>[expression, call],
                             HIs.VARIABLE_CHECK);
     } else if (RuntimeTypes.hasTypeArguments(type)) {
       Element element = type.element;
       Element helper = backend.getCheckSubtype();
       HInstruction helperCall = new HStatic(helper);
       add(helperCall);
       HInstruction representations =
         buildTypeArgumentRepresentations(type);
       add(representations);
-      HInstruction isFieldName =
-          addConstantString(node, backend.namer.operatorIs(element));
+      String operator =
+          backend.namer.operatorIs(backend.getImplementationClass(element));
+      HInstruction isFieldName = addConstantString(node, operator);
       // TODO(karlklose): use [:null:] for [asField] if [element] does not
       // have a subclass.
       HInstruction asFieldName =
           addConstantString(node, backend.namer.substitutionName(element));
       List<HInstruction> inputs = <HInstruction>[helperCall,
                                                  expression,
                                                  isFieldName,
                                                  representations,
                                                  asFieldName];
       HInstruction call = new HInvokeStatic(inputs, HType.BOOLEAN);
@@ skipping 2439 matching lines @@
           new HSubGraphBlockInformation(elseBranch.graph));
 
     HBasicBlock conditionStartBlock = conditionBranch.block;
     conditionStartBlock.setBlockFlow(info, joinBlock);
     SubGraph conditionGraph = conditionBranch.graph;
     HIf branch = conditionGraph.end.last;
     assert(branch is HIf);
     branch.blockInformation = conditionStartBlock.blockFlow;
   }
 }